The subject matter herein relates generally to an electrical device having a temperature sensing device with an insulation displacement contact.
Temperature sensors, such as negative temperature coefficient (NTC) thermistors or positive temperature coefficient (PTC) thermistors, are used in many high amperage applications for monitoring the temperature of components for the purpose of safety and operation. For example, plug-in electric vehicles (EVs), including all-electric cars and plug-in hybrids, receive power from an electric vehicle charging station, also called an Electric Vehicle Supply Equipment (EVSE) through a standardized interface, such as, a plug connector for coupling with a mating receptacle connector of the EV, such as an interface defined by an industry standards SAE J1772, IEC 62196, VDE-AR-E 2323-2-2, EV-Plug Alliance, and/or CHAdeMO. The plug connector is electrically connected to a power source through a high amperage circuit and provides power to the EV according to an industry standard or level. As an example, an EVSE providing power according to a Level 2 alternating current (AC) charging standard, may provide up to 80 Amps charging current to the connected EV.
Resistive heating, also referred to as joule heating or ohmic heating, occurs in the high amperage circuit at discrete locations, such as junctions and/or connection points that connect the components of the EVSE and EV. In addition, resistive heating may increase at these locations due to various parameters or conditions, such as manufacturing tolerances, mechanical ageing and reduction of contact pressure, chemical corrosion or oxidation of mating surfaces, or misuse and abuse leading to degraded performance. Potentially, increased resistance may lead to overheating and damage to the components of the EVSE and/or EV during operation.
For reasons such as safety, cost, and/or design parameters, temperature sensors are not placed in direct contact with the discrete locations to be monitored. Rather, temperature sensors are positioned at a distance from the connection point to indirectly or passively sense the temperature through a thermally conductive path between the discrete location and the temperature sensor. For example, to monitor temperature fluctuations of the connection point between a connector and wire conductor, the temperature sensor may attach to an outer surface, such as an insulated jacket of the wire conductor, of the wire conductor at a distance along the wire conductor from the connection point with an attachment member, such as a spring clip, a metal grasping clip, a clamp, and the like. The resistive heat at the connection point conducts through the thermally conductive path defined by the wire conductor, insulated jacket, and attachment member to the temperature sensor. The effectiveness of the temperature sensor to rapidly and accurately sense the temperature changes at the connection point is related to the length and thermal conductivity of the thermally conductive path. Thus, as the length increases and the thermal conductivity lowers, the effectiveness of the temperature sensor decreases. In addition, the attachment members may be subject to environmental conditions, such as vibration, temperature, and the like that decrease the effectiveness of the temperature sensor.
Accordingly, there is a need for a temperature sensing device that effectively senses temperature changes at a connection point.